User talk:94.21.242.1

December 2020
Hello, I'm ComplexRational. I noticed that you added or changed content in an article, Group (periodic table), but you didn't provide a reliable source. It's been removed and archived in the page history for now, but if you'd like to include a citation and re-add it, please do so. You can have a look at the tutorial on citing sources. If you think I made a mistake, you can leave me a message on my talk page. Thank you. ComplexRational (talk) 16:18, 23 December 2020 (UTC)
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